单项选择题
A.in sight of one another in fog
B.navigating in or near an area of restricted visibility
C.only if they are showing special purpose lights
D.only if they have operational radar
单项选择题 The Rules state that certain factors are to be taken into account when determining safe speed. Those factors include（）.
单项选择题 The Rules state that certain factors are to be taken into account when determining safe speed. One of the factors is the（）.
单项选择题 The rules require that a stand-on vessel SHALL take action to avoid collision when she determines that（）.